The present invention relates to gable top containers, and more particularly to the top closure seal of a gable top container prepared from a blank of sheet material, as for example, paperboard. The invention finds utility in the manufacture of gable top containers for use in packaging fluids, for example, milk, juices, syrups and other liquid products. An object of the present invention is to eliminate so called "top leakers".
Gable top containers are presently in use for a number of liquid applications. Their style is well known to most users from school children to adults. Such containers are generally prepared from paperboard having their overall inner and outer surfaces coated with a thermoplastic coating, i.e., low density polyethylene (LDPE), which allows the containers to be side seamed under heat and pressure for shipping, and ultimately bottom formed and top closed with the aid of heat and pressure when the containers are formed and filled. Depending upon the products packaged in such containers, the paperboard structure may include other polymer layers to provide barriers to the ingress or egress of oxygen, flavors, or odors. In any event, such containers start out in the form of blanks of the paperboard laminate which are cut into shape and impressed with an appropriate pattern of score lines to define the side panels, bottom closure flaps and top closure flaps. More often than not, the integrity of the seals made to form the carton are just as important as the actual laminate construction, particularly where a long shelf life is desired. The increased amount of material used in making large size containers makes the control of the folding and sealing operations even more critical because of the increased possibility of creating fluid escape channels where multiple thicknesses of sheet material are sealed together.
U.S. Pat. Nos. 3,334,799 and 3,471,076 each show a means for closing the channel that is formed in the region of the top seal of a gable top container. The means shown in these patents involves the addition of tufts to the upper edges of the inner rib panels wherein when the carton is formed, the tufts lie opposite one another at one or more spaced locations along the edges of the panels. Thus when the containers employing the designs of the '076 and '079 patents are sealed, the tufts are pressed together to hopefully block the channel. Unfortunately the mass and integrity of the generally small tufts used in the past are often compromised during blank production and during the subsequent filling and top closing operation. In addition, with the tufts placed opposite one another they can create an inconsistent seal for the top closure flaps of the container, thus becoming actually counterproductive. A related structure is also shown in U.S. Pat. No. 3,189,246, wherein two tabs are opposed in the top closure of a gable top container, but it suffers from the same defects of the aforementioned patents.
It is therefore an object of the present invention to provide a new and improved gable top closure with effectively sealed fluid escape channels.
Another object of the present invention is to provide a container of the general type disclosed which has an extensible pouring spout which can easily be released and extended by the consumer.
These and other objects will become more apparent by reference to the drawings and the detailed description.